This project is designed to develop a culture medium and environment which will enable type II cells to maintain differentiated functions in long term primary culture. The two functions to be studied are synthesis of surfactant phospholipids at levels approaching those for freshly isolated and cultured cells and the maintenance of enzyme activity associated with the microsomal mixed function oxidase system. The project is divided into 2 parts. The first will evaluate the isolation method for type II cells including use of proteolytic enzyme, method of lung exposure to it and supplementation of isolation medium. This will allow isolation of cells in the best possible condition. Using type II cells isolated according to these results, a culture medium will be developed containing hormones and other factors which will help maintain the differentiated properties listed above. The second portion of this project will evaluate type II cells on a extracellular matrix or its components. These will include fibronectin, laminin and a cellular lung sponge. The development of a long term primary culture of type II cells with retention of differentiated functions will remove a major restriction to the use of this cell in the study of pulmonary biology.